Metal forming machine



Sept. 10, 1946. A. EpNELsoN METAL FORMING MACHINE Filed Feb. 8, 1945 UR mm 8 mm .m A X M BY .i

. nrroxwer Patented Sept. 10, 1946 2,407,573 METAL FORMING MACHINE Alex E. Nelson, Los Angeles, Calif.,. assignor to H Douglas Aircraft Company, Inc., Santa Monica,

Calif.

iUNlTED STATES PATENT OFFICE f Application February 8, 1943, Serial No. 475,193

13 Claims. (01. 78-61) This invention relates to a machine-for forming metal and particularly to a machine for shrinking or stretching sheet metal.

Sh'eets of metal inltheir finalfabricatedform or'at some intermediate stage in-the" process of fabrication may have a surface shape or a condi- "tion requiring correction.- The sheet 'may be planar and havelocalized bulges or ridges. It

may have a generally cylindrical or other-curvilinear shape interrupted by local deformations.

Or it may have a plane surface or generally curved surface in which itis desired to'form bulges or other local deviations from its general surface contour. Or a sheet of metal may have the desired surface contour but possess internal stresses which are of a weakening or otherwise h'armful character in view of the use to which it is to be put. In many such cases a machine of this invention is of useful application.

It has heretofore been practiced to shrink or stretch sheet metal along straight or curved lines in one direction only. Two pairs of gripping dies or jaws are used, each pair contacting a surface of the metal sheet and the two dies of a pair moving toward and away from each other along a singlestraight or curvilinear directional line. The die surfaces are roughened to grip the metal sheet so that in the shrinkingmachine as they approach each other they may push the metal particles together, thickening the sheet along transverse lines and shortening the sheet longitudinally, and in a stretching machine as they move apart they may similarly elongate a sheet. Processing of sheet metal in accordance with this prior practice is limited for the most part to shrinking and stretching of relatively narrow strips of sheet metal which it is desired to shorten or. elongate as a whole or along only one edge portion thereof. For it is mechanically difiicult to mount and operate dies of this type which are long enough to reach from side to side of a wide sheet. If shorter dies are used, the metal just beyond the ends of the strip which is being acted upon by the dies inhibits the shrinking action of the dies upon the metal within the strip.

Again the single directional shrinking is an inefficient way of removing cans or local bulges from a metal sheet or of eliminating internal stresses apt to cause cans or otherwise interfere with the use of the sheet. Such defects, be-

cause of their two dimensional character are not usually readily eliminated by upsetting the metal in asingle directional manner.

-eThe machine of this invention involvesessentially the upsetting of sheet metal, while held 1mmovably to a surface contour, by forces acting in all radial directions, but in the same sense, with -a centripetal sense the result is a shrinking of the metal toward the center. The machine of the invention may be utilized toredistribute the metal in a sheet to remove bulges, to form bulges,

to eliminate internal stress, to shorten or elongate either narrow or wide strips of sheet metal,

3 either as a whole or along one edge portion thereof and to thicken or thin sheet metal either in local areas spaced from the edges'of the sheet or in bands extending to the edges of the sheet. Shortening or elongating a wide sheet, or otherwise correctively forming it over elongated zones or strips, may be accomplished by repeatedly applying the machine at aligned loci.

It is one object of the invention to provide a. machinefor upsetting a sheet af metal centripetally or centrifugally while it is constrained to a prescribed surface contour.

It is another object of the invention to provide a machine for the fulfillment of the above object by means of two sets of sector shaped dies arranged with their apexes at'a common center and, capable of moving radially with respect to the center from an initial position.

It is another object of the invention to provide for the resilient return of the dies of such a machine to their initial position.

It is another object of the invention to provide for the registering axial alignment of the dies of one set with the corresponding dies, respectively, of the other set.

It is another object of the invention to provide a die machine for centrally shrinking the metal in a, generally circular zone of a metal sheet, which shall provide for the above described resilient return andregistering alignment of the dies.

While the machine described below represent one embodiment of the invention which is designed for centripetal shrinking of sheet metal, other sheet metal shrinking machines may likewise embody the invention. The invention may dies and die holder therefor taken along the line plane in a direction normal to the flange. If the 22 of Figure 1. shrinking dies are applied to this flange with their Figure 3 is a side elevation of one of the sets of axial center adjacent to the outer edge 54 of the dies. flange at spaced intervals along the flange, the

Figure 4 is an enlarged plan view of one of the 5 metal of the flange is crowded together to a varydies. ing extent, the action of the dies being such as to Figure 5 is a perspective view of a flanged memthicken and shorten the metal to a maximum ber, illustrating .;'a, cs work artic-len'livhich; maypbe Tde gree; adja'centithe edge 54;1the degreecof thick- 7 processed by -a mac-hineof this invention. a l ening an'd shortening "decreasing' across' the flange An upper die holder iii and a lower die holder 10 and reaching zero at the joint line 48. A pair of 12 are mounted on a machine (not shown). which z dies moving in a single direction to and from each provides means for moving the upper sdie holder --other,as.,i n,prior practice, are obviously operating toward the lower die holder to effect a pressural at 'a'disadvantage, the metal near the Web resistrelation of the dies with aisheetggoinnetals-ll l ,dis-

inglthecmovementsof the dies and inhibiting the posed therebetween. The lup'per- 'die holder: t!) has 15 desired shrinkageof the metal near the edge 54.

a conically bottomed recess IS in its lower face. A machine constructed in accordance with this The lower die holder l2 is similarlyrformed I ,in zention -wilLmore the metal readily, wherever its upper face with arecess I8. applied. If any portion of the metal resists move- 7 The recesses I6 and I8 each hold zen-equal; :xment dile to its surface contour or'to adjacent number of sector shaped dies 20, which are sized stiffening metal formations, such as the web 50, iand. Shaped 1' so that when; their; rim i aces 2 2 ,enthexdiescontactingathat portionate deto;have less ijgflgellthei cylindliflal SideKWQHHZA,"of'j'thfijl eQessf of amovementrelative tattle-w rk bject t q hQl rthezcorrespond n GiehQklHr QB--wa11s :26;of;:a1[1y and the opp it d e to avelgr a erm men wozpmximate dieswar se ar te bra eara e relatire to the orlsob ct causingqasL sh tpaceaniandthe"apexestilrof the di es araspaced g-of thgv rk object. T iS- ieaturec th "insmallidistance fIOmgthe axial ce nt e r rsz l f the h venti nentsi he.ma hg eror ierholding recess. In -the; drawing ach-die holdierent kinds -loi work articleseand i r isshownas:mountingxightdies. 'rnurnber-of Idifferent results. v

Retaining; pinsiM, cthreadedlyasecured jngjihe This-,ieaturexis 1sm 'acjcant ge their acylindrioaliwallscefiofethe dieholdersen age an-r30 ,nrinsi-e o :t e' invention bed e .ierturesitfidn.theldiesgtwpreventrotationa1:moveystretchi-ngm chi il wh q e heg 1 4 1 ---mentrofi-the dies .andzaccidental:disassemb1y. of ration are moved outwardly alon hr. :;;the:rdiesif-r0m ;the;;diei;holder. [These-apertures maanfl ni i ohnormal, cen hposi rare dimensioned ito cpermitllimited. longitudinal ,caxi'a-l movement-of theidies. l I .zrspringsfllflgseatfid'ln recessestlt2 in; the;side1walls 1:26; ofir thedies hold the: dies; resiliently; apartzto instance; in, el m nat n rin-ternal nsi e 'essesiina-fian n d-,t0..-;a;web-t H rel m ved ioinihlm -v i r theextent permittedvby; the :walls 0f 17h6;di.hQld- .I; claim:

ing recesses. V 1 V 1. In a deviceiorproducingagchangepf io gm ":Therwolk contactingrefacesi ldiiof the diesrare io a; piece: oi;-sheet.;meta 1, the cornbination of: -.sandeblasted .or otherwiseroughened:to1prevent zi'wo eetsofgrippin -i s;t ees ts being m vab the idiessslipping. on the sheetumetal 'workr, article. ;t;owar.r1can,draway:fro 8 91 Qilhfilfnfil ldxfiw The opposite end faceofeaichdie hasthershape pri ing 1&1 astthree; sector;s;h aped iof-ra' conical :se'ctor :conformingctosthembottom of 'the recess. A vfiherrjinl the operation ofithe' machinerthe dies i o'f thetwo sets are -brought intoecontact with the :opposite side's;respectively, of a -sheet of :metal which is to be processed as -for in'stance -td be l0ca'11yshrur ikto eliminate-ta planardeviation such:as' a can: or bulge; the axiallyacting pres sure of the machine :causes the:sixteen dies to moveicentrally 'by reason ofIthe'cam-action of the' comically v shaped bottom l faces :oi the 'two firecesses i6 and il'fi. --A. ciroular porti'on of the lZ $kmefiin$i r fiifi ylmQYj said ,J 1;

metal sheet containing at leasta or-tion of the as mer ensesfrom sai zinitialzposition withiltesnoct bulge: is gripped and pressed'intothe general wtorsai rc nter. V

i-verseIy sloping cam surfaces;or sothg tzmeanfina =p1ane-of the sheet and'themet'al thereof is moved :2. .-Th ---comhina i defined rinzblaizmji i towardthe eentral axis 32 of the die rholders, :adfil 0n1thereto;,:means.;forresilientiyrretrieving shrinking slightly= the total area-of the portion 1 cos-S aWs: O v-the initial position. as measured before-beingfiattened betweenthe h ombina ,Qn ldefmfid dmelaim 1 1,.ofin

-"tion as-shownin Fig-ur'e 2.

dies so that when the die pressure is releasedthe ='wh fi ssa d:fi stsandcsecond; meanseincludemam slack-of the bu-lgeis goneand thesheet-cannot Q1 $h I -spring-back to itsi bulged condition. ''U-pon-regr ite:ztheilt rippingrfacesmfiorx ;a generally *lease oi'thepressureoi 'the' dies' when the npper':65 conical surfaceacoaxia withasaid ivtcentensand *die holder-it is"retractivelyelevated;the springs .i-f Ether-include oppos ngzp essure memhersrhav- MWretu-rn the dies to-their norma1 or initiaLposig worrespondingzcooperating conicallyiashaped uriacesrthereon. V v l A machineof the invention has many fields of ia'idevice' for producingcacchangesofi:iorm

use in forming sheet metal bodies. -For-example, :lO-z nazpiec 'sheetrmetal, 1the-.ucombinaition-.sof:

a flange 46 shown in Figure 5, which is integrally ittwowsetszof, ripping jawsgithersetsrbeingcrriovasble '-joined t0 a webEfi on a c'onvexly curved jointline -towandicandaway.fromzealch.othergkmdreachsaid 4:48 lying in the plane of. the flange, quite frequenltset comprising atprleasti:threensector:shapedcjaws 1y has a surface contour presenting .scallopelike their-.apexes aicommonscenterianditheir --WW6S g r Wrinkles departing from its. general 3.75 rinnin iaces it aired rtosiform aiconmlonasubstan iacesxof; said :iawszof reach ;:set;:ops tially circular surface juxtaposed to a similar cooperating common substantially circular surface formed by the gripping faces of the other each two proximate jaws; a first means for axially relatively moving the jaws of each set toward the other set to press them against a work sheet; and a second means acting coordinately with said axially moving means for radially moving said jaws of each set against the resilient action of the mounting means to diminish the clearance spaces.

5. In a device for producing a change of form metal, the combination of:

gripping faces faired to form a common substantially circular surface juxtaposed to a similar cooperating common surface formed by the other set of jaws; means mounting the jaws of each set to hold them resilsockets in the sides of said proximate jaws.

7. The combination defined in claim 1, and in addition thereto; means for preventing rotative movement of said jaws in said mounting means.

8. The combination defined in claim 1 in which said mounting means are held non-rotatively and in addition thereto; interacting means on each of said jaws and the mounting means therefor 9. A device for shrinking a, metal sheet comprising two jaw housing members movable towards and away from each other, a plurality of gripping jaws reciprocally disposed side by side in each housing member with the outer ends of one set of jaws facing the outer ends of the other set of jaws, the jaws of each set being relatively movable laterally in a manner to shrink the sheet other to move at least two directions.

10. In a device for producing a change of form in a piece of sheet metal, the combination of:

two sets of gripping jaws, the sets being movable toward and away from each other, and each set comprising at least three jaws disposed with their sheet gripping faces in juxtaposed on a common the other set to press both sets against a work sheet; and a second means acting coordinately with said. first means for moving said jaws in said radial manner and in the same sense.

to a similar cooperating common by the gripping faces 

